32 visiting now: 16 USA 
9 Singapore 
5 Canada 
2 Belgium 
2 China 
1 UK 
1 Czech Republic 
1 Iran 
1 Russia 
9 Singapore 5 Canada 2 Belgium 2 China 1 UK 1 Czech Republic 1 Iran 1 Russia 9 Singapore 5 Canada 2 Belgium 2 China 1 UK 1 Czech Republic 1 Iran 1 Russia